(1) Field of the Invention
The present invention generally relates to a spray tower for improving contact between a gas stream and a fluid such as a liquid, slurry, or the like. In particular, the present invention is directed to perforated plate covering a cross-section of the spray tower that is aligned with spray nozzles thereby forcing gas into the dense stream of the fluid.
(2) Description of the Related Art
Generally, open spray towers can be used for heat exchange purposes, for the removal of entrained solids and/or liquids in a gas, or for chemical interchanges. One form of a gas and fluid contact system is used for the removal of acid gases such as sulfur dioxide, hydrogen chloride, hydrogen fluoride from flue gases. Typically, the fluid selected is a fluid of limestone and gypsum, or the like, which is sprayed through multiple levels of spray nozzles, thereby providing contact with the acidic flue gas.
In the case of calcium-based flue gas desulfurization, such as limestone slurry scrubbing, there is a fixed dissolved alkalinity in the sprayed slurry, which is depleted rapidly. After depletion, the drops no longer scrub SO2 or scrub it slowly. Spray nozzles are typically arranged in a manner to cover a portion of the area of the spray tower. A portion of the gas contacts the slurry and reacts. However, there is much gas that only contacts a depleted spray and therefore no, or only a slight reaction, occurs.
Generally, the spray nozzles are arranged so that the sprays overlap to cover a larger area. Still, much of the gas does not contact the spray. One way maldistribution is reduced is by using a custom spray integrated into the tray and support structure or by disturbing stratification at the wall of the absorber. Also, typical practice to improve gas liquid distribution is to stagger nozzle layout, such that nozzles are not in vertical alignment, therefore covering a larger area. However, these methods still do not show great improvement in the area of maldistribution.